Information

EP-2016-247

(Submitted on 05 Oct 2016)

Tools

Contact

Abstract

The decays $B^+\rightarrow J/\psi 3\pi^+ 2\pi^-$ and $B^+\rightarrow \psi(2S)
\pi^+\pi^+\pi^-$ are observed for the first time using a data sample
corresponding to an integrated luminosity of $3.0fb^{-1}$, collected by the
LHCb experiment in proton-proton collisions at the centre-of-mass energies of 7
and 8 TeV. The branching fractions relative to that of $B^+ \rightarrow
\psi(2S)K^+$ are measured to be \begin{eqnarray*}
\frac {\mathcal{B}\left(B^+\rightarrow J/\psi 3\pi^+ 2\pi^- \right)}
{\mathcal{B}\left(B^+ \rightarrow \psi(2S)K^+ \right)}
& = &
\left(1.88\pm0.17\pm0.09\right)\times10^{-2},
\frac {\mathcal{B}\left(B^+\rightarrow \psi(2S) \pi^+\pi^+\pi^- \right)}
{\mathcal{B}\left(B^+ \rightarrow \psi(2S)K^+ \right)} & = &
\left(3.04\pm0.50\pm0.26\right)\times10^{-2}, \end{eqnarray*} where the first
uncertainties are statistical and the second are systematic.

(a) Mass distribution of the selected $ B ^+ \rightarrow { J \mskip -3mu/\mskip -2mu\psi \mskip 2mu} 3\pi ^+ 2\pi ^- $ candidates with
the additional requirement
of every $ { J \mskip -3mu/\mskip -2mu\psi \mskip 2mu} \pi ^+ \pi ^- $ combination to be outside of $\pm6 {\mathrm{\,MeV\!/}c^2} $ around
the known $\psi {(2\mathrm{S})}$ mass.
The total fit function,
the $ B ^+$ signal contribution and
the combinatorial background are shown
with thick solid\,(orange),
thin solid\,(red) and dashed\,(blue) lines, respectively.
(b) Sum of mass distributions for all possible backgrounddash-subtracted
$\pi ^+ \pi ^- $ combinations.
The factorisationdash-based model prediction is shown by a solid\,(red) line,
and the expectation from the phasedash-space model
is shown by a dashed\,(blue) line.
The total fit function, shown with a dotted\,(green) line, is an incoherent sum of
a relativistic Breitdash-Wigner function with
the mean and natural width fixed to the known $\rho ^{0}$ values
and a phasedash-space function multiplied by a seconddash-order polynomial.